Change _rs_allocate so it can combine the two regions (rs and rsx)

into one if a system has an awesome getentropy().  In that case it
is valid to totally throw away the rsx state in the child.  If the
getentropy() is not very good and has a lazy reseed operation, this
combining is a bad idea, and the reseed should probably continue to
use the "something old, something new" mix.  _rs_allocate() can
accomodate either method, but not on the fly.
ok matthew

1 files changed, 17 insertions, 14 deletions

diff --git a/src/lib/libc/crypt/arc4random.h b/src/lib/libc/crypt/arc4random.h
index e0309a3184..d867687226 100644
--- a/src/lib/libc/crypt/arc4random.h
+++ b/src/lib/libc/crypt/arc4random.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: arc4random.h,v 1.1 2014/07/18 02:05:55 deraadt Exp $  */
+/*      $OpenBSD: arc4random.h,v 1.2 2014/07/19 00:08:41 deraadt Exp $  */
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -22,25 +22,28 @@
  * Stub functions for portability.
  */
 
-static inline void *
-_rs_allocate(size_t len)
+static inline int
+_rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
 {
-        void *p;
+        struct {
+                struct _rs rs;
+                struct _rsx rsx;
+        } *p;
 
-        if ((p = mmap(NULL, sizeof(*rs), PROT_READ|PROT_WRITE,
+        if ((p = mmap(NULL, sizeof(*p), PROT_READ|PROT_WRITE,
             MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
-                return (NULL);
-        return (p);
-}
+                return (-1);
+        if (minherit(p, sizeof(*p), MAP_INHERIT_ZERO) == -1) {
+                munmap(p, sizeof(*p));
+                return (-1);
+        }
 
-static inline void
-_rs_forkdetect(void)
-{
+        *rsp = &p->rs;
+        *rsxp = &p->rsx;
+        return (0);
 }
 
 static inline void
-_rs_forkdetectsetup(struct _rs *rs, size_t len)
+_rs_forkdetect(void)
 {
-        if (minherit(rs, len, MAP_INHERIT_ZERO) == -1)
-                abort();
 }